Commercial and industrial storage tanks are widely used for storing a great variety of liquids. Some of these liquids are highly corrosive and/or are flammable. The service life of a storage tank will vary, depending upon environmental conditions, including the liquid being stored. Eventually, however, the tank will become corroded and develop leaks, thereby necessitating either the repair of the leak or the complete removal of the tank and replacement with a new tank. Whether the tank is repaired or replaced will depend upon the economics of the situation as well as local ordinances or regulations governing the integrity of commercial and industrial storage tanks. For example, certain storage tanks are commonly used for storing gasoline at service stations. Gasoline, of course, is highly flammable and poses a significant health and safety hazard if not properly contained. Federal as well as local regulations govern the structure of such storage tanks.
Under certain conditions, it is possible that a storage tank which has developed a leak can be properly repaired without removing it from the earth. This is desired because the removal of a buried storage tank, which can range up to 40,000 gallons in capacity, is extremely costly and time consuming. A conventional method of repairing a damaged tank involves applying a coating of polyester or epoxy coating material to the entire interior of the tank. When the material is properly applied, the repaired tank has the same integrity as a new tank. In other instances, it is necessary to remove a storage tank from the ground and replace it with a new storage tank, meeting all the federal and local safety regulations.
Heightened public awareness of the danger posed by storage tanks (particularly underground gasoline storage tanks) has led to additional governmental regulations. Recent regulations will soon require most storage tanks to have secondary containment means and possibly a fail safe design feature to guard against accidental soil, water and air contamination. Secondary containment means must be capable of containing liquid leaked from the storage tank. Rigid vaulted tanks have been suggested as one alternative. While effective for containment purposes, such tanks are costly and difficult to install because of their weight. A rigid tank with a jacket or bladder as disclosed in my U.S. Pat. Nos. 4,523,454 and 4,524,609 also provides secondary containment means and avoids the problems associated with the vaulted systems. Additionally, the aforementioned jacket and bladder systems feature a fail-safe design due to the fact they provide continuous monitoring means whereby the integrity or both the primary and secondary containment means are checked to ensure that leakage of either containment means is known when it first occurs.
There has now been discovered a method whereby new and used storage tanks can be provided with secondary containment means in a convenient, yet economical manner. Further, used storage tanks are refurbished to a standard equivalent to that possessed by a new tank and then upgraded to have a secondary containment feature.